This invention relates to the chiral total synthesis of the known antibiotic (+)-thienamycin (I): ##STR1## More specifically, this invention relates to a process for preparing methyl 2,6-dideoxy-.alpha.-D-arabinohexopyranoside (III) from methyl 2-deoxy-.alpha.-D-glucopyranoside (II) by a regioselective halogenation and hydrogenolysis step. The following iodination/hydrogenolysis scheme is preferred and illustrative: ##STR2## Compound III, methyl 2,6-dideoxy-.alpha.-D-arabinohexopyranoside, is useful in the total synthesis of (+)-thienamycin in a manner which is described and claimed in concurrently filed, commonly assigned U.S. Patent applications Ser. Nos. 248,177, now U.S. Pat. No. 4,384,998, 248,116, now U.S. Pat. No. 4,324,900 and 248,174 filed Mar. 30, 1981 of Philippe L. Durette. These co-pending, commonly assigned applications are hereby incorporated by reference to the extent that they disclose the utility for compound III. Also incorporated herein by reference is co-pending commonly assigned U.S. Patent application Ser. No. 112,058 filed Jan. 14, 1980, now abandoned which is directed to a process for the total synthesis of thienamycin, which total synthesis crosses at an intermediate common to said process disclosed in U.S. Ser. No. 248,177 filed Mar. 30, 1981. Also incorporated by reference are U.S. Pat. No. 4,234,596 (issued 11-18-80), and EPO Application No. 79,101,307-1 filed 5-1-79 (publication No. 0007973), which publications disclose schemes of total synthesis which can be fed by common intermediates made available by the presently disclosed and claimed process.